From Washington.
It is announced, that 15,000 Confederate troops are monating siege guns at Fairfax Court-House.
Several Federal officers, as a reward for their courage in the recent battles, have been authorized to raise regiments.
New regiments are being constantly accepted.
The Michigan Regiment lost 9 officers and 108 men, at the battle near Manassas, on Sunday the 21st inst. This regiment went into the field with 475.
It is announced here that, the Southerners are concentrating at Winchester. Much uneasiness is apprehended of an attack at Harper's Ferry.
Washington, July 27.--Gen. McClellan has arrived. A committee from New York is here, who are urging the Government to place Gen. Wool in a position of active employment.
In the Senate a bill has been passed to define and punish conspiracies, and for the suppression of rebellion.
